• The Korean Journal of Physiology and Pharmacology
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• 제6권3호
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• pp.139-142
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• 2002

To examine intracellular signaling of human $S1P_3\;(hS1P_3),$ a sphingosine 1-phosphate (S1P) receptor in plasma membrane, $hS1P_3$ DNA was transfected into RH7777 rat hepatoma cell line, and the inhibition of forskolin-induced cAMP accumulation and activation of MAP kinases by S1P were tested. In $hS1P_3$ transformants, S1P inhibited forskolin-induced activation of adenylyl cyclase activity by about 80% and activated MAP kinases in dose-dependent and pertussis-toxin (PTX) sensitive manners. In oocytes expressing $hS1P_3$ receptor, S1P evoked $Cl^-$ conductance. These data suggested that PTX-sensitive G proteins are involved in $hS1P_3-mediated$ signaling, especially the positive action of S1P in cell proliferation. The potential advantages of rat hepatoma cells for the research of sphingosine 1-phosphate receptor are discussed.

• 약학회지
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• 제47권3호
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• pp.180-183
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• 2003

Crystal structure of TRAF6 in complex with TRAF6-binding sites from CD40 was previously determined. The structure revealed a distinct TRAF6-binding groove of CD40, the key structural determinant of interaction. The structural information leads to a proposed TRAF6-binding motif. This allows the identification of TRAF6-binding sequences in the hIRAK protein, whose functional requirement in IL-1/Toll-like receptor superfamilies-mediated signal transduction is further demonstrated using site-directed mutagenesis. The mutational effects of hIRAK on the down-stream NF-kB signaling shows the importance of the TRAF6 interface for signaling by IL-1/Toll-like receptor superfamilies.

• Genomics & Informatics
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• 제19권2호
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• pp.18.1-18.8
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• 2021

G protein–coupled receptors (GPCRs), including olfactory receptors, account for the largest group of genes in the human genome and occupy a very important position in signaling systems. Although olfactory receptors, which belong to the broader category of GPCRs, play an important role in monitoring the organism's surroundings, their actual three-dimensional structure has not yet been determined. Therefore, the specific details of the molecular interactions between the receptor and the ligand remain unclear. In this report, the interactions between human olfactory receptor 1A1 and its odorant molecules were simulated using computational methods, and we explored how the chemically simple odorant molecules activate the olfactory receptor.

• Asian Pacific Journal of Cancer Prevention
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• 제15권13호
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• pp.5325-5330
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• 2014

Background: Chronic myelocytic leukemia is a disease that threatens both adults and children. Great progress has been achieved in treatment but protein-protein interaction networks underlining chronic myelocytic leukemia are less known. Objective: To develop a protein-protein interaction network for chronic myelocytic leukemia based on gene expression and to predict biological pathways underlying molecular complexes in the network. Materials and Methods: Genes involved in chronic myelocytic leukemia were selected from OMIM database. Literature mining was performed by Agilent Literature Search plugin and a protein-protein interaction network of chronic myelocytic leukemia was established by Cytoscape. The molecular complexes in the network were detected by Clusterviz plugin and pathway enrichment of molecular complexes were performed by DAVID online. Results and Discussion: There are seventy-nine chronic myelocytic leukemia genes in the Mendelian Inheritance In Man Database. The protein-protein interaction network of chronic myelocytic leukemia contained 638 nodes, 1830 edges and perhaps 5 molecular complexes. Among them, complex 1 is involved in pathways that are related to cytokine secretion, cytokine-receptor binding, cytokine receptor signaling, while complex 3 is related to biological behavior of tumors which can provide the bioinformatic foundation for further understanding the mechanisms of chronic myelocytic leukemia.

• The Korean Journal of Physiology and Pharmacology
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• 제15권6호
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• pp.383-388
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• 2011

Regulators of G-protein signaling (RGS) proteins are regulators of $Ca^{2+}$ signaling that accelerate the GTPase activity of the G-protein ${\alpha}$ -subunit. RGS1, RGS2, RGS4, and RGS16 are expressed in the pancreas, and RGS2 regulates G-protein coupled receptor (GPCR)-induced $Ca^{2+}$ oscillations. However, the role of RGS4 in $Ca^{2+}$ signaling in pancreatic acinar cells is unknown. In this study, we investigated the mechanism of GPCR-induced $Ca^{2+}$ signaling in pancreatic acinar cells derived from $RGS4^{-/-}$ mice. $RGS4^{-/-}$ acinar cells showed an enhanced stimulus intensity response to a muscarinic receptor agonist in pancreatic acinar cells. Moreover, deletion of RGS4 increased the frequency of $Ca^{2+}$ oscillations. $RGS4^{-/-}$ cells also showed increased expression of sarco/endoplasmic reticulum $Ca^{2+}$ ATPase type 2. However, there were no significant alterations, such as $Ca^{2+}$ signaling in treated high dose of agonist and its related amylase secretion activity, in acinar cells from $RGS4^{-/-}$ mice. These results indicate that RGS4 protein regulates $Ca^{2+}$ signaling in mouse pancreatic acinar cells.

• 한국자기공명학회논문지
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• 제9권2호
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• pp.74-92
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• 2005

The high resolution solution structure of MCP-3 was determined using multinuclear, multidimensional NMR spectroscopy with an expressed and $^{13}C-\;and\;^{15}N-labeled$ protein. The MCP-3 has a typical chemokine fold including 3 anti-parallel $\beta-sheets$, and a C-terminal helix, but it exists as a monomer in solution under the conditions where the structure was determined (2 mM, pH 5.1 at $30^{\circ}C$). Based on the structure and the amino acid sequence compared to other chemokines we propose that Ile20 and Leu25 in MCP-3 play key roles in the formation of N-loop (residues between the $2^{nd}$ cysteine and the I sheet) which has been implicated as a determinant of chemokine specificity. Additional receptor binding surface is supplied by the 40s loop (residues between the 2 and the 3 sheet) and the binding interface of the acidic N-terminal region of chemokine receptor to MCP-3 would resemble the dimerization interface of CC type dimer.

• Tuberculosis and Respiratory Diseases
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• 제44권6호
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• pp.1271-1284
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• 1997

연구배경 : 종양괴사인자(tumor necrosis factor ; TNF)는 다양한 생물학적 기능을 가지고 있는 바, 그 중 생체 외에서 증명된 뚜렷한 항암 효과로 말미암아 최근 항암 유전자요법의 중요한 대상으로 관심을 모으고 있다. 현재 유전자 이입의 기술적 문제로 생체 외에서 암세포에 유전자 이입을 시행한 후 이를 다시 환자의 생체내로 이식하는 방법이 연구의 주종을 이루고 있다. 그러나 저자들의 과거의 연구를 포함한 여러 연구에서 TNF가 이입된 암세포는 TNF에 대해 내성을 보이는 것으로 증명되었고 이에는 새로이 방어 단백질을 합성하는 것이 관여할 것이라는 시사가 있었다. 이 획득내성의 기전을 밝히는 것이 종양생물학의 이해를 넓히고 보다 효과적인 항암 유전자요법을 개발하기위한 매우 중요한 과제로 생각된다.

• BMB Reports
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• 제40권5호
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• pp.783-790
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• 2007

Receptor binding plays an important role in determining host specificity of the Bacillus thuringiensis Cry $\delta$-endotoxins. Mutations in domains II and III have suggested the participation of certain residues in receptor recognition and insect specificity. In the present study, we expressed the cloned domain II-III fragment of Cry4Ba and examined its binding characteristics to mosquito-larval midgut proteins. The 43-kDa Cry4Ba-domain II-III protein over-expressed in Escherichia coli as inclusion bodies was only soluble when carbonate buffer, pH 10.0 was supplemented with 4M urea. After renaturation via stepwise dialysis and subsequent purification, the refolded domain II-III protein, which specifically reacts with anti Cry4Ba-domain III monoclonal antibody, predominantly exists as a $\beta$-sheet structure determined by circular dichroism spectroscopy. In vitro binding analysis to both histological midgut tissue sections and brush border membrane proteins prepared from susceptible Aedes aegypti mosquito-larvae revealed that the isolated Cry4Ba-domain II-III protein showed binding functionality comparable to the 65-kDa full-length active toxin. Altogether, the data present the 43-kDa Cry4Ba fragment comprising domains II and III that was produced in isolation was able to retain its receptor-binding characteristics to the target larval midgut proteins.

• The Korean Journal of Physiology and Pharmacology
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• 제19권2호
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• pp.141-149
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• 2015

"G protein-coupled receptor 40" (GPR40), a receptor for long-chain fatty acids, mediates the stimulation of glucose-induced insulin secretion. We examined the profiles of differential gene expression in GPR40-activated cells treated with linoleic acid, and finally predicted the integral pathways of the cellular mechanism of GPR40-mediated insulinotropic effects. After constructing a GPR40-overexpressing stable cell line (RIN-40) from the rat pancreatic ${\beta}$-cell line RIN-5f, we determined the gene expression profiles of RIN-5f and RIN-40. In total, 1004 genes, the expression of which was altered at least twofold, were selected in RIN-5f versus RIN-40. Moreover, the differential genetic profiles were investigated in RIN-40 cells treated with $30{\mu}M$ linoleic acid, which resulted in selection of 93 genes in RIN-40 versus RIN-40 treated with linoleic acid. Based on the Kyoto Encyclopedia of Genes and Genomes Pathway (KEGG, http://www.genome.jp/kegg/), sets of genes induced differentially by treatment with linoleic acid in RIN-40 cells were found to be related to mitogen-activated protein (MAP) kinase- and neuroactive ligand-receptor interaction pathways. A gene ontology (GO) study revealed that more than 30% of the genes were associated with signal transduction and cell proliferation. Thus, this study elucidated a gene expression pattern relevant to the signal pathways that are regulated by GPR40 activation during the acute period. Together, these findings increase our mechanistic understanding of endogenous molecules associated with GPR40 function, and provide information useful for identification of a target for the management of type 2 diabetes mellitus.

• The Korean Journal of Physiology and Pharmacology
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• 제17권2호
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• pp.139-147
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• 2013

Lysolipids such as LPA, S1P and SPC have diverse biological activities including cell proliferation, differentiation, and migration. We investigated signaling pathways of LPA-induced contraction in feline esophageal smooth muscle cells. We used freshly isolated smooth muscle cells and permeabilized cells from cat esophagus to measure the length of cells. Maximal contraction occurred at $10^{-6}M$ and the response peaked at 30s. To identify LPA receptor subtypes in cells, western blot analysis was performed with antibodies to LPA receptor subtypes. LPA1 and LPA3 receptor were detected at 50 kDa and 44 kDa. LPA-induced contraction was almost completely blocked by LPA receptor (1/3) antagonist KI16425. Pertussis toxin (PTX) inhibited the contraction induced by LPA, suggesting that the contraction is mediated by a PTX-sensitive G protein. Phospholipase C (PLC) inhibitors U73122 and neomycin, and protein kinase C (PKC) inhibitor GF109203X also reduced the contraction. The PKC-mediated contraction may be isozyme-specific since only $PKC{\varepsilon}$ antibody inhibited the contraction. MEK inhibitor PD98059 and JNK inhibitor SP600125 blocked the contraction. However, there is no synergistic effect of PKC and MAPK on the LPA-induced contraction. In addition, RhoA inhibitor C3 exoenzyme and ROCK inhibitor Y27632 significantly, but not completely, reduced the contraction. The present study demonstrated that LPA-induced contraction seems to be mediated by LPA receptors (1/3), coupled to PTX-sensitive G protein, resulting in activation of PLC, PKC-${\varepsilon}$ pathway, which subsequently mediates activation of ERK and JNK. The data also suggest that RhoA/ROCK are involved in the LPA-induced contraction.